Caries attack rates for permanent teeth of children are greatly influenced by the duration of exposure to risk. To better access caries susceptibility, it was decided to determine the eruption patterns of the children being studied. Using the dental findings of 37,066 children examined during the l979-80 National Dental Caries Prevalence Survey, an estimation of the time of eruption for permanent teeth was made for children ages 4-18. Circulations were made of the percentages of children having each tooth at each age. Ages for the survey were rounded to the nearest birthdate. Eruption patterns were calculated for each upper and lower tooth by sex and race. Probit analysis were used to establish time of eruption and corresponding confidence limits. The age at eruption of mandibular teeth was usually earlier than maxillary teeth, though some teeth, such as 2nd bicuspids, erupted at about the same time in both arches. As expected, there is a definite hierarchy of eruption by race and sex, with teeth erupting earlier in females than in males and in blacks earlier than in whites. The largest difference in age of eruption occurred in upper and lower cuspids, which erupted approximately one and a quarter years earlier in black females than in white males. Comparing our results with past studies of white children in the U.S., it appears that the teeth of present day white children are erupting earlier.